It is well-known that when teeth, such as bucket teeth, are used in abrasive conditions, the material of each tooth wears at a quick rate due to the abrasive action of the material being worked. The increased wear rate shortens the useable life of the tooth plus during use the tooth normally becomes blunt as illustrated in FIG. 21 of U.S. Pat. No. 4,187,626 issued Feb. 12, 1980 to D. J. Greer, et al. As the tooth becomes blunt due to wear, its ability to penetrate the material being worked is decreased. Forcing a blunted tooth to penetrate the material being worked requires additional effort, thus reducing operating efficiency.
Attempts have been made to increase wear life and maintain sharpness during the useful life of the tooth. Two examples are U.S. Pat. Nos. 3,286,379 and 3,805,423 each respectively issued Nov. 22, 1966 to J. G. Benetti and Apr. 23, 1974 to H. L. Engel, et al. Each of these patents illustrate the application of a hard material insert or a hard weld material being applied to the top surface of the tooth. These designs would appear to aid in increasing wear life and maintaining a degree of sharpness during the useful life of the tooth. However, in each case, the bottom surface of the respective teeth are still subjected to increased wear rates since the unprotected bottom surface of each tooth is still in direct contact with the material being worked.
Another attempt of increasing wear life while maintaining sharpness is illustrated in U.S. Pat. No. 4,083,605 which issued Apr. 11, 1978 to M. A. College, et al. The tooth of this design is designed for use on a ripper. The tooth has inserts of hard material disposed in a "U" pattern with the legs of the "U" being the leading edge and the trailing edge of the tooth. Once one leg of the "U" is worn away, the tooth can be turned around to expose the unused leg of the "U" pattern for extended life of the tooth. During use on a ripper, only the bottom and the leading leg of the "U" is exposed to wear. Consequently, there is no need to provide added protection to the trailing leg as compared to the need to protect the bottom surface on a bucket tooth.
The present invention is directed to overcoming one or more of the problems as set forth above.